Yep, oak larders are the way to go. You can use Stealing Creation hammers which give you 2x bonus xp, which save money+time (although these wont work on double xp). Get your butler to get 24 oak planks out of the bank, make 2 oak larders, send him to get more, make and remove the last oak larder, rinse and repeat. Don't use a BoB, you're using a butler instead. Use a demon butler if you can, if not just use the highest level butler you can. You could just join the cc 'housesw31' which is full of people who are willing to lend their gilded alter. EDIT: from 46 con, you could get to 69 con and then use tea+crystal saw. You would use 10002 oak planks costing 6.4m